For the average healthy person, eating a serving (about 1 cup or 20-30 grapes) daily is linked to positive outcomes for the heart, brain, and overall inflammation. The “cause for concern” applies only to those with specific conditions like IBS, CKD, or those on certain medications, or when grapes are consumed in extreme excess.
The bottom line: If you are on blood thinners, have kidney disease, or suffer from digestive disorders, consult your doctor about your grape intake. For everyone else, the biggest risk is probably just buying a bunch and eating them all in one sitting—which, as far as health habits go, is one of the better problems to have.
